The present embodiments relate to reperfusion mapping. In particular, destruction timing is provided for three-dimensional reperfusion qualitative or quantitative analysis.
Three-dimensional perfusion parametric images of ultrasound contrast agents are useful for studying variations in blood flow in organs and tissues in response to disease states, drugs, or other physiological conditions. Destruction-reperfusion sequencing is a well known technique for measuring contrast agent perfusion within an organ or other tissue. For volume perfusion parametric imaging, contrast agent is introduced into the bloodstream and then a region of agent in a cross-section plane is destroyed with high energy ultrasound. The region is then imaged in a non-destructive contrast sensitive mode to measure blood perfusion parameter, such as contrast agent arrival time, maximum intensity projection, normalized time integral, or maximum area coverage. A collection of planar cross sections acquired in sequence can be combined to form a volume data set.
The individual planar cross-sections are formed from a mechanically translated one-dimensional array or from a fully electronically scanned two-dimensional array. In one example, a one-dimensional array is mechanically translated in elevation to create a series of two-dimensional images of a destruction-reperfusion contrast agent arrival time parameter. Each two-dimensional image is individually motion compensated over the destruction-reperfusion cycle for the plane. The collection of two-dimensional images representing the arrival time or rate of perfusion for individual elevation slices are then combined to form the volume data set. The volume data set is used for rendering in three-dimensional or for multiplanar reformatting. However, if there is significant motion during consecutive slice acquisition periods, then the synthesized volume image may not be an accurate representation of the three-dimensional perfusion parameters. Out-of-plane motion may cause geometric distortion and regions which may be skipped or rescanned.
Destruction energy may be steered in response to motion so that the desired region experiences the required destruction energy, and the same region is then tracked and measured during the reperfusion phase. However, this approach may require that the destruction energy be steered in potentially arbitrary directions. The arbitrary direction may be difficult or unattainable for certain object and probe geometries. In addition, some transducers cannot easily scan arbitrary planes and are limited to orthogonally placed line sequences. Arbitrary positioning is difficult with a mechanically translated 1D array since transducer positioning cannot be accomplished at a high frame rate (i.e. 10 Hz) due to mechanical inertia of the transducer and positioning apparatus.